NAME

ExtUtils::MakeMaker::FAQ - Frequently Asked Questions About
MakeMaker

DESCRIPTION

FAQs, tricks and tips for "ExtUtils::MakeMaker".
Module Installation
How do I keep from installing man pages?
Recent versions of MakeMaker will only install man pages
on Unix like operating systems.
For an individual module:
perl Makefile.PL INSTALLMAN1DIR=none INSTALLMAN3DIR=none
If you want to suppress man page installation for all
modules you have to reconfigure Perl and tell it 'none'
when it asks where to install man pages.
How do I use a module without installing it?
Two ways. One is to build the module normally...
perl Makefile.PL
make
...and then set the PERL5LIB environment variable to
point at the blib/lib and blib/arch directories.
The other is to install the module in a temporary loca-
tion.
perl Makefile.PL PREFIX=~/tmp LIB=~/tmp/lib/perl
And then set PERL5LIB to ~/tmp/lib/perl. This works
well when you have multiple modules to work with. It
also ensures that the module goes through its full
installation process which may modify it.
Philosophy and History
Why not just use <insert other build config tool here>?
Why did MakeMaker reinvent the build configuration
wheel? Why not just use autoconf or automake or ppm or
Ant or ...
There are many reasons, but the major one is cross-
platform compatibility.
Perl is one of the most ported pieces of software ever.
It works on operating systems I've never even heard of
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(see perlport for details). It needs a build tool that
can work on all those platforms and with any wacky C
compilers and linkers they might have.
No such build tool exists. Even make itself has wildly
different dialects. So we have to build our own.
What is Module::Build and how does it relate to MakeMaker?
Module::Build is a project by Ken Williams to supplant
MakeMaker. Its primary advantages are:
* pure perl. no make, no shell commands
* easier to customize
* cleaner internals
* less cruft
Module::Build is the official heir apparent to MakeMaker
and we encourage people to work on M::B rather than
spending time adding features to MakeMaker.
Module Writing
How do I keep my $VERSION up to date without resetting it manu-
ally?
Often you want to manually set the $VERSION in the main
module distribution because this is the version that
everybody sees on CPAN and maybe you want to customize
it a bit. But for all the other modules in your dist,
$VERSION is really just bookkeeping and all that's
important is it goes up every time the module is
changed. Doing this by hand is a pain and you often
forget.
Simplest way to do it automatically is to use your ver-
sion control system's revision number (you are using
version control, right?).
In CVS, RCS and SVN you use $Revision: 1.3 $ (see the
documentation of your version control system for
details) writing it like so:
$VERSION = sprintf "%d.%03d", q$Revision: 1.3 $ =~ /(\d+)/g;
Every time the file is checked in the $Revision: 1.3 $
will be updated, updating your $VERSION.
In CVS version 1.9 is followed by 1.10. Since CPAN com-
pares version numbers numerically we use a sprintf() to
convert 1.9 to 1.009 and 1.10 to 1.010 which compare
properly.
If branches are involved (ie. $Revision: 1.3 $) its a
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little more complicated.
# must be all on one line or MakeMaker will get confused.
$VERSION = do { my @r = (q$Revision: 1.3 $ =~ /\d+/g); sprintf "%d."."%03d" x $#r, @r };
What's this META.yml thing and how did it get in my MANIFEST?!
META.yml is a module meta-data file pioneered by
Module::Build and automatically generated as part of the
'distdir' target (and thus 'dist'). See "Module
Meta-Data" in ExtUtils::MakeMaker.
To shut off its generation, pass the "NO_META" flag to
"WriteMakefile()".
XS
How to I prevent "object version X.XX does not match bootstrap
parameter Y.YY" errors?
XS code is very sensitive to the module version number
and will complain if the version number in your Perl
module doesn't match. If you change your module's ver-
sion # without reruning Makefile.PL the old version
number will remain in the Makefile causing the XS code
to be built with the wrong number.
To avoid this, you can force the Makefile to be rebuilt
whenever you change the module containing the version
number by adding this to your WriteMakefile() arguments.
depend => { '$(FIRST_MAKEFILE)' => '$(VERSION_FROM)' }
How do I make two or more XS files coexist in the same directory?
Sometimes you need to have two and more XS files in the
same package. One way to go is to put them into separate
directories, but sometimes this is not the most suitable
solution. The following technique allows you to put two
(and more) XS files in the same directory.
Let's assume that we have a package "Cool::Foo", which
includes "Cool::Foo" and "Cool::Bar" modules each having
a separate XS file. First we use the following
Makefile.PL:
use ExtUtils::MakeMaker;
WriteMakefile(
NAME => 'Cool::Foo',
VERSION_FROM => 'Foo.pm',
OBJECT => q/$(O_FILES)/,
# ... other attrs ...
);
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Notice the "OBJECT" attribute. MakeMaker generates the
following variables in Makefile:
# Handy lists of source code files:
XS_FILES= Bar.xs \
Foo.xs
C_FILES = Bar.c \
Foo.c
O_FILES = Bar.o \
Foo.o
Therefore we can use the "O_FILES" variable to tell Mak-
eMaker to use these objects into the shared library.
That's pretty much it. Now write Foo.pm and Foo.xs,
Bar.pm and Bar.xs, where Foo.pm bootstraps the shared
library and Bar.pm simply loading Foo.pm.
The only issue left is to how to bootstrap Bar.xs. This
is done from Foo.xs:
MODULE = Cool::Foo PACKAGE = Cool::Foo
BOOT:
# boot the second XS file
boot_Cool__Bar(aTHX_ cv);
If you have more than two files, this is the place where
you should boot extra XS files from.
The following four files sum up all the details dis-
cussed so far.
Foo.pm:
-------
package Cool::Foo;
require DynaLoader;
our @ISA = qw(DynaLoader);
our $VERSION = '0.01';
bootstrap Cool::Foo $VERSION;
1;
Bar.pm:
-------
package Cool::Bar;
use Cool::Foo; # bootstraps Bar.xs
1;
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Foo.xs:
-------
#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"
MODULE = Cool::Foo PACKAGE = Cool::Foo
BOOT:
# boot the second XS file
boot_Cool__Bar(aTHX_ cv);
MODULE = Cool::Foo PACKAGE = Cool::Foo PREFIX = cool_foo_
void
cool_foo_perl_rules()
CODE:
fprintf(stderr, "Cool::Foo says: Perl Rules\n");
Bar.xs:
-------
#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"
MODULE = Cool::Bar PACKAGE = Cool::Bar PREFIX = cool_bar_
void
cool_bar_perl_rules()
CODE:
fprintf(stderr, "Cool::Bar says: Perl Rules\n");
And of course a very basic test:
test.pl:
--------
use Test;
BEGIN { plan tests => 1 };
use Cool::Foo;
use Cool::Bar;
Cool::Foo::perl_rules();
Cool::Bar::perl_rules();
ok 1;
This tip has been brought to you by Nick Ing-Simmons and
Stas Bekman.

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